Enhancement by lead acetate of body weight-decreasing activity of endotoxin: quantitative comparisons of some administration methods of lead acetate.

The body weight-decreasing effect of sublethal doses of endotoxin was enhanced in mice administered with such an amount of lead acetate that had no effect by itself on body weight. The enhancing effects of administration of lead acetate prior to, simultaneously with and after endotoxin administration were analyzed and compared by statistical methods. Linear dose-response relation between logarithmic doses of endotoxin and body weight-decreasing responses was obtained over a wide range of endotoxin doses with a constant dose of lead acetate. The non-parallelism between two dose-response lines obtained in lead acetate-treated and control mice was not denied. The relation of the two lines indicated that the more minute the dose of endotoxin, the more intense the enhancing effect of lead acetate appearing in the treated mice within certain limits of minute doses of endotoxin. These results were common in the three administration methods of lead acetate and can be applied to detection of minute doses of endotoxin. It was suggested that the pre-administration method of lead acetate was more suitable for detection of endotoxin than the other methods.